Other features include a new fuel-efficient power system and upgraded hydraulics.The C-Series line includes the Cat 579C for large timber, clear cutting and severe delimbing applications, and the Cat 559C loader for pine, pulpwood and thinning. Controlled tests by Cat have shown productivity improvements of 22% between the 559B and 559C loaders, while using the same amount of fuel. The C-Series is powered by the 129.5 kW (174 hp) Cat C6.6 ACERT engine, which meets US Tier 4 Interim emissions standards. Fuel consumption is reduced with an automatic idle down feature and a variable speed engine fan that only cools according to requirements.
The 579C has 35% more lift at full reach, while the 559C lifts 25% more at full reach. The standard knuckleboom reach is 9.8 m (32 ft). There are three operating modes to choose from. Economy mode provides fast cycle times and the best fuel economy. The Run mode provides more hydraulic power for demanding jobs. The Power mode provides the most power for heavy duty delimbing. An increase in the hydraulic line size accelerates grapple opening and closing.
The 579C now has a right-side operators cab with a walk-up platform and enlarged doorway for easy access to the cab. A number of other improvements have been made and features added. Source: http://www.cat.com/cda/layout?m=251101&x=7&id=4391915